Tuesday

The world's richest individuals have placed $11.5 trillion of assets in offshore havens, mainly as a tax avoidance measure. The shock new figure - 10 times Britain's GDP - is contained in the most authoritative study of the wealth held in offshore accounts ever conducted.

The study, by Tax Justice Network, a group of accountants and economists concerned at the escalating wealth held in offshore locations, shows that the world's high-net-worth individuals earn $860 billion each year from their assets.

But there is growing alarm among regulators and campaigners because exchequers worldwide are missing out on at least $255bn of tax each year. Governments appear unable, or unwilling, to prevent the rich employing aggressive strategies to minimise their tax liabilities.

The OECD this weekend confirmed that international tax avoidance is a growing problem that troubles governments not just of rich countries, but middle-income ones as well.

'This is one of the defining crises of our times,' said John Christensen, co-ordinator of the Tax Justice Network and a former economic adviser to the Jersey government. 'One of the most fundamental changes in our society in recent years is how money and the rich have become more mobile. This has resul ted in the wealthy becoming less inclined to associate with normal society and feeling no obligation to pay taxes.'

James Jones, Anglican Bishop of Liverpool, said: 'In this country, we have created a culture of tax avoidance. The current debate is pandering to a culture of consumption and avoidance. We need a much better debate than the political parties are currently giving us.'

Individuals such as Rupert Murdoch, Philip Green, Lakshmi Mittal and Hans Rausing - among the world's richest men - all make extensive use of tax havens.

There is nothing illegal about placing assets and cash offshore, but campaigners are promising to attack tax avoidance by the world's richest people in much the same way that they currently target environment and trade issues.

The $11.5trn does not include the vast amount of money stashed in tax havens by multinational corporations, which are using increasingly sophisticated techniques to run rings round the authorities.

The Tax Justice Network study has drawn from data supplied by the Bank of International Settlements, Merrill Lynch and McKinsey. Richard Murphy of Tax Research, who co-authored the report, said: 'No one has tried to calculate a number like this before. To ensure the credibility of our data, we have only used information already in the public domain and produced by some of the most authoritative sources in the world.

'In addition, we tested our conclusions against three independent sources of information, and all seem to substantially agree, giving us a high degree of confidence in the conclusions.'

'Gordon Brown and the British government are ideally placed to act on offshore tax avoidance, since so many of the banks and tax havens that facilitate these processes have British links,' said Charles Abugre, Christian Aid's head of policy.

'Only last week, the Commission for Africa called for an immediate doubling of aid to Africa to help it meet the Millennium Development Goals. And yet here is a potential source of revenue that even the most responsible governments are doing little to tap into.'